The present invention relates to a device for dissipating heat and cutting off power of a pump, which can resist relatively high temperature, and automatically cut off the power of the pump when the pump has been racing to cause the temperature of the pump to rise beyond a certain amount due to lack of water.
Referring to FIG. 5, a conventional pump 3 has a motor 31, a shaft center 311, a main shaft 33, a fixing member 32, a protecting member 34, a ceramics ring 341, a rear sealing cover 35, a shaft seal 361, a main blade wheel 36, an O-shaped ring 381, a middle cover 37, a single phase valve 371 and a main body 38.
The shaft center 311 sticks out on the center of the front end of the motor 31 for passing on movement to the main shaft 33, which is connected to the shaft center 311. The fixing member 32 is stationary. The motor 31 is fixedly connected to one side of the fixing member 32 from the front end.
The protecting member 34 and the rear sealing cover 35 are fixedly connected to the fixing member 32. The main blade wheel 36 is disposed next to the front side of the rear sealing cover 35. The shaft seal 361 is passed through the rear sealing cover 35, the protecting member 34 and the main blade wheel 36. The main shaft 33 is passed through the sealing cover 361 to connect the main blade wheel 36 by means of a screw 362 so that the main blade wheel 36 can turn together with the main shaft 33 when the motor is running. The middle cover 37 and the single phase valve 371 are disposed next to the main blade wheel 36 in the main body 38, which is connected to the rear sealing cover 35 with the O-shaped ring 381 being disposed in between for sealing up the joint therebetween.
The shaft seal 361 is tightly passed into the protecting member, and will not turn together with the main blade wheel 36 so water will not flow to the motor 31 when the main blade wheel 36 turns to pump water. The protecting member 34 is made of soft plastic materials so that same and the ceramics ring 341 passed into the protecting member 34 have watertight connection. The shaft sealing cover 361 is tightly passed into the protecting covering 34 as above mentioned, and further tightly passed into the ceramics rings 341 from the front end portion so that water won""t flow through the joints to the motor 31 to damage the same.
The motor 31 will cause high temperature in running and the large amount of heat will pass through the shaft seal 361 and the main blade wheel 36, and is dissipated by water pumped into the pump. The ceramics ring 341 is disposed between the protecting member 34 and the front end portion of the shaft seal 361 mainly because it has relatively good conductivity and heat resisting ability to dissipate heat for preventing the plastic protecting member 34 from being melted by the large amount of heat.
However, the conventional pump with the heat dissipating ceramics ring still has drawbacks as follows:
1. The motor will race due to lack of water, and produce a large amount of heat, which can not be dissipated because there is no enough flowing water in contact with the main blade wheel. Consequently the large amount of heat will pass through the plastic protecting member and the rear sealing cover to damage same.
2. When the plastic protecting member is melted, water will flow through apertures between same and the shaft seal to the motor, and cause the motor to get damaged.
3. The motor will also be damaged by the high temperature caused by the racing thereof due to lack of water.
Therefore, it is a main object of the present invention to provide a device to a pump that can dissipate heat and cut off power automatically when the motor of the pump has been racing to cause a high temperature due to lack of water.
The device for dissipating heat and cutting off power of a pump in the present invention includes a heat dissipating ceramics ring and a power cutting-off member.
The ceramics ring is tightly fitted in a pivoted hole of a plastic member. The pump has a motor with a shaft passing through a shaft seal to connect a main blade wheel provided for pumping water. The shaft seal is fitted in the ring from a front end portion, and fitted in the plastic member to form a watertight connection. The ceramics ring has an annular trench forming between an outer and an inner annular portions for increasing contact area of both of the annular portions with water so that the ring can dissipate heat more rapidly. Thus, the plastic member is protected from getting melted by heat from the motor.
The power cutting off device is connected to the motor, and has a sensing element disposed in contact with the ceramics ring to sense a temperature of same for activation of the power cutting-off member when a racing of the motor occurs to cause temperatures of both the motor and the ceramics ring rising.